apache / apache/pekko-persistence-cassandra
Cassandra 5.0 Unified Compaction Strategy (UCS)
- Dominant language
- Scala
- Stars
- 15
- Forks
- 17
- Avg merge
- 6h 43m
- Merged PRs (30d)
- 11
Description
### Discussed in https://github.com/apache/pekko-persistence-cassandra/discussions/363
Originally posted by **EmadAlblueshi** January 27, 2026
Hello Everyone,
The current compaction strategy employed for the Apache Cassandra tables is `SizeTieredCompactionStrategy` which is fine for version 4 but version 5 is using `UnifiedCompactionStrategy` as the default strategy and [recommended ](https://cassandra.apache.org/doc/stable/cassandra/managing/operating/compaction/ucs.html)
> The UnifiedCompactionStrategy (UCS) is recommended for most workloads, whether read-heavy, write-heavy, mixed read-write, or time-series. There is no need to use legacy compaction strategies, because UCS can be configured to behave like any of them.
Do we have any plans to update the current tables to use `UnifiedCompactionStrategy `in line with version 5 best practices?
Contributor guide
Research direction
Start with discussion 363, then locate the current Cassandra table definitions and compaction-strategy configuration in the repository. Compare the existing setup with Cassandra 5.0's UnifiedCompactionStrategy guidance; the work is done when the applicable tables use the intended strategy consistently.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cassandra, scala
- Domain
- databases
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100